1,2-diphenyl-2-propen-1-one derivatives

ABSTRACT

The present invention provides compounds represented by the following formula [I] or salts thereof which lower intraocular pressure by causing morphological change in trabecular meshwork cells. In the formula, R1 is H, lower alkyl, hydroxy, lower alkoxy or halogen, R2, R3 and R4 are H or lower alkyl, and . . . is a single bond or a double bond. When R3 and/or R4 is hydrogen, the amino can be protected by a protecting group.

This application is a U.S. National Phase application under 35 USC 371of International Application PCT/JP00/00094 (not published in English)filed Jan. 12, 2000.

TECHNICAL FIELD

The present invention relates to novel compounds which are useful astherapeutic agents for glaucoma.

BACKGROUND ART

In general, glaucoma is a disease wherein visual functions sufferdisorders caused by a rise of intraocular pressure. Aqueous humoroutflow is closely related to the rise of intraocular pressure. When theaqueous humor outflow is disturbed, the intraocular pressure rises. Theaqueous humor flows mainly from trabecular meshwork through a Schlemm'scanal outside an eyeball. The aqueous humor outflow can be increased byreducing resistance of the aqueous humor outflow in this trabecularmeshwork. Cells which form the trabecular meshwork (trabecular meshworkcells) have sulfhydryl groups. A method of lowering the intraocularpressure has been reported, in which a compound capable of reacting withthe sulfhydryl groups is administered so as to make a morphologicalchange in the trabecular meshwork cells and increase the rate of aqueoushumor outflow. (Japanese Examined Patent Publication No. 13013/1995).This patent Publication discloses phenoxyacetic acid derivatives,preferably ethacrynic acid as compounds capable of reacting with thesulfhydryl groups.

The method of lowering the intraocular pressure by causing themorphological change in the trabecular meshwork cells is veryinteresting as a method of treating glaucoma. However, there have notbeen so many studies of drugs having such a function mechanism yet. Astudy of creating new drugs in development of therapeutic agents forglaucoma is a very interesting subject.

DISCLOSURE OF THE INVENTION

Accordingly, noting that ethacrynic acid, which is a phenoxyacetic acidderivative having an α,β-unsaturated carbonyl group, has an effect ofcausing the morphological change in the trabecular meshwork cells andlowering the intraocular pressure, the present inventors synthesizedvarious novel compounds and studied their effects on morphology of thetrabecular meshwork cells. As a result, the present inventors found thatnovel 1,2-diphenyl-2-propen-1-one derivatives, that is, compounds havinga 1,2-diphenyl-2-propen-l-one structure as a basic structure and anamino group introduced into their side chain of the benzene ring at the1st-position, have excellent effects. Thus, the present invention hasbeen completed.

The present invention relates to compounds represented by the followinggeneral formula [I] and salts thereof (hereinafter referred to as “thepresent compound” as far as there is no proviso), and pharmaceuticalcompositions containing them as active ingredients:

wherein R¹ is hydrogen, lower alkyl, hydroxy, lower alkoxy or halogen,R², R³ and R⁴, being the same or different, are hydrogen or lower alkyl,and . . . is a single bond or a double bond.

The groups defined above are described in detail hereinafter.

The lower alkyl is straight-chain or branched alkyl having one to eightcarbon atoms such as methyl, ethyl, propyl, butyl, hexyl, isopropyl,isobutyl, isopentyl, isohexyl, t-butyl or 3,3-dimethylbutyl.

The lower alkoxy is straight-chain or branched alkoxy having one toeight carbon atoms such as methoxy, ethoxy, propoxy, butoxy, hexyloxy,isopropoxy or t-butoxy.

The halogen is fluorine, chlorine, bromine or iodine.

When R³ and/or R⁴ is hydrogen in the present compounds, the amino groupcan be protected by a protecting group. The protecting group of theamino group is a general protecting group of an amino group such asacyl, ester, substituted lower alkyl or substituted sulfonyl. In detail,examples of the protecting group are acyl such as formyl, loweralkanoyl, halogeno-lower alkanoyl or phenylcarbonyl; ester such as loweralkoxycarbonyl, substituted lower alkoxycarbonyl or phenoxycarbonyl;substituted lower alkyl such as allyl, phenyl-lower alkyl orbenzoyl-lower alkyl; and substituted sulfonyl such as loweralkylsulfonyl or phenylsulfonyl. Each phenyl ring of the above-mentionedphenylcarbonyl, phenoxycarbonyl, phenyl-lower alkyl, benzoyl-lower alkyland phenylsulfonyl can be substituted by halogen, lower alkyl, loweralkoxy or nitro.

Specific examples of preferred protecting groups of the amino group areacyl such as formyl, acetyl, trichloroacetyl, trifluoroacetyl orbenzoyl; ester such as methoxycarbonyl, isobutoxycarbonyl,t-butoxycarbonyl, allyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl,benzyloxycarbonyl, diphenylmethoxycarbonyl or phenoxycarbonyl;substituted alkyl such as allyl, benzyl, trityl or(4-methoxyphenyl)diphenylmethyl; and substituted sulfonyl such asbenzenesulfonyl, 2,4,6-trimethylbenzenesulfonyl or toluenesulfonyl.

When R¹ is hydroxy, the hydroxy can be protected by a general protectinggroup similarly to amino protection.

Salts in the present invention refer to any pharmaceutically acceptablesalts and are exemplified by salts with an inorganic acid such ashydrochloric acid, nitric acid or sulfuric acid, salts with an organicacid such as acetic acid, fumaric acid, maleic acid, citric acid ortartaric acid and the like. When there are geometrical isomers oroptical isomers in the present compounds, these isomers are alsoincluded in the present invention.

The present compounds can be in the form of solvates such as hydrates.

Preferred examples of the present compound are compounds wherein thegroup(s) is (are) the followings in the compounds represented by thegeneral formula [I] or salts thereof,

(1 a) R¹ is a group selected from hydrogen, lower alkyl and halogen;and/or

(2 a) R² is hydrogen; and/or

(3 a) both R³ and R⁴ are lower alkyl.

Namely,

Compounds defined by above (1 a) in the compounds represented by thegeneral formula [I] or salts thereof,

Compounds defined by above (2 a) in the compounds represented by thegeneral formula [I] or salts thereof,

Compounds defined by above (3 a) in the compounds represented by thegeneral formula [I] or salts thereof, and

Compounds defined by any combinations of two or more of above (1 a), (2a) and (3 a) in the compounds represented by the general formula [I] orsalts thereof.

The most preferred examples of the present compound are the followingcompounds and salts thereof.

1) 1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl-2-phenyl-2-propen-1-one

2) 1-[4-[3-(Dimethylamino)propyl]phenyl-2-phenyl-2-propen-1-one

The present invention also relates to compounds represented by thefollowing general formula [IV], which are synthetic intermediates of thecompounds represented by the above general formula [I], and saltsthereof:

wherein R¹, R², R³, R⁴ and . . . have the same definitions as mentionedabove, and >X is >CHOH or >C═O. When R³ and/or R⁴ is hydrogen, the aminogroup can be protected by protecting group(s).

A typical synthetic route of the present compound [I] is shown below.

The above synthetic route does not represent all methods, but onetypical example. Details of specific synthetic methods are described inlater Examples.

A synthetic method of the above route is described in detail below.

The aminoalcohol [II] (compound wherein >X is >CHOH in the compoundrepresented by the general formula [IV] and salts thereof) is treated inthe presence of an Oxidizing agent (for example, dimethyl sulfoxide(DMSO)) to give the carbonyl compound represented by the formula [III](compound wherein >X is >C═O in the compound represented by the generalformula [IV] and salts thereof). Next, the compound [III] is condensedwith paraformaldehyde in the presence of a secondary amine by Mannichreaction, and then the present compound [I] is obtained by eliminationreaction.

When the reactants have a hydroxy group or an amino group in theirmolecule in the above-mentioned synthetic method, the group can beprotected optionally by a suitable protecting group, and the protectinggroup can also be removed by a conventional method after the reaction.

The present compounds are novel compounds which are unknown inliteratures, and are characterized in that the present compounds have a1,2-diphenyl-2-propen-1-one structure, that is, the compounds have anα,β-unsaturated carbonyl group substituted by two benzene rings, as abasic structure, and an amino group is introduced into a side chain ofthe benzene ring at the 1st-position.

As described above in the section of “Background Art”, it was reportedthat ethacrynic acid has an effect of lowering intraocular pressure bymaking a morphological change in trabecular meshwork cells andincreasing the rate of aqueous humor outflow (see Japanese ExaminedPatent Publication No. 13013/1995). Ethacrynic acid is a phenoxyaceticacid derivative having an α,β-unsaturated carbonyl group. Focusingattention on this chemical structure of ethacrynic acid, the presentinventors studied precisely and found that novel compounds exhibitinghigher effects are obtained by introducing one benzene ring into theα-position of ethacrynic acid and by further introducing an amino groupinto the side chain of the other benzene ring.

Administration methods of drugs can be a method of administering activecompounds themselves or a method of administering the drugs in the formto be decomposed in vivo and to be converted into the active compounds,namely in the form of prodrugs. Both are widely used. When the presentcompounds have a hydroxy group or an amino group protected by a suitableprotecting group in their molecules, the present compounds can beadministered with the hydroxy group or the amino group protected by theprotecting group. The present compounds can also be administered afterremoving the protecting group to convert the protected group into thehydroxy group or the amino group.

In order to study utility of the present compounds, effects of thepresent compounds on morphology of the trabecular meshwork cells wereinvestigated. Details will be described later in the section of“Pharmacological Test”, and morphological changes of the trabecularmeshwork cells by adding the present compounds were studied by imageanalysis. As a result, the present compounds exhibited excellent cellmorphology change effects on the trabecular meshwork cells. Accordingly,the present compounds are considered to have excellent intraocularpressure-lowering effects.

The present compound is mainly administered parenterally and can also beadministered orally. Examples of dosage forms are eyedrops, injections,tablets, capsules, granules and the like. The present compound can beformulated into preparations by conventional methods. For example,eyedrops can be prepared by optionally using an isotonic agent such assodium chloride or concentrated glycerine; a buffer such as sodiumphosphate or sodium acetate; a surfactant such aspolyoxyethylenesorbitan monooleate, polyoxyl 40 stearate orpolyoxyethylene hydrogenated castor oil; a stabilizer such as sodiumcitrate or disodium edetate; a preservative such as benzalkoniumchloride or paraben; or the like. pH can be in a range acceptable forophthalmic preparations, and it is preferably in a range of 4 to 8. Oralpreparations such as tablets, capsules and granules can be prepared byoptionally using a diluent such as lactose, starch, crystallinecellulose or vegetable oil; a lubricant such as magnesium stearate ortalc; a binder such as hydroxypropylcellulose or polyvinyl pyrrolidone;a disintegrator such as calcium carboxymethylcellulose; a coating agentsuch as hydroxypropylmethylcellulose, macrogol or silicone resin; or agelatin film-forming agent.

The dosage of the present compound can be selected suitably depending onsymptoms, age, dosage form and the like. In the case of eyedrops, theyare instilled once to several times per day with a concentration of0.001 to 3% (w/v) solution. In the case of oral preparations, the usualdaily dosage is 1 to 1000 mg, which can be given in a single dose orseveral divided doses.

Preparations, formulations and results of pharmacological test of thepresent compounds are shown below. These examples do not limit the scopeof the present invention, but are intended to make the present inventionmore clearly understandable.

BEST MODE FOR CARRYING OUT THE INVENTION PREPARATION COMPOUNDS REFERENCEEXAMPLE 1

4-(Phenylacetyl)cinnamic Acid (Reference compound No. 1-1)

1) Thionyl chloride (3.3 ml) is added dropwise to a solution of ethyl4-carboxycinnamate (2.0 g) in chloroform (4 ml) under a nitrogenatmosphere, then dimethylformamide (one drop) is added thereto, and themixture is refluxed for 30 minutes. The reaction mixture is concentratedunder reduced pressure to give a residue of corresponding acid chloride.The residue is dissolved in tetrahydrofuran (30 ml) under a nitrogenatmosphere, and the solution is cooled with dry ice. A 2.0 M solution ofbenzylmagnesium chloride in tetrahydrofuran (4.5 ml) is added dropwisethereto. Twelve minutes after completing the addition, a 10% aqueouscitric acid solution is added to the reaction mixture under dry icecooling, then the temperature is raised to room temperature, and thewhole is extracted with ether. The organic layer is washed with waterand saturated brine successively, dried over anhydrous magnesium sulfateand concentrated under reduced pressure. The resulting residue ispurified by silica gel column chromatography to give ethyl4-(phenylacetyl)cinnamate (675 mg) as crystals.

mp 110.5˜111.3° C.; IR (KBr, cm⁻¹) 2986, 1690, 1410, 1330, 1206, 970,704.

2) A 1 N aqueous sodium hydroxide solution (2.3 ml) and water (4 ml) areadded to a solution of ethyl 4-(phenylacetyl)cinnamate (675 mg) inethanol (6 ml)-tetrahydrofuran (6 ml) under a nitrogen atomosphere, andthe mixture is stirred at room temperature for 6.5 hours. To thereaction mixture is added 1 N hydrochloric acid to acidify it, and thewhole is extracted with ethyl acetate. The organic layer is washed withsaturated brine, dried over anhydrous magnesium sulfate and concentratedunder reduced pressure. The resulting precipitates are filtered off togive the titled compound (Reference compound No. 1-1) as crystals.

(Reference compound No. 1-1)

mp 232˜236° C. (decomp.); IR (KBr, cm⁻¹) 3036, 2589, 1684, 1630, 1337,1230, 993.

The following compounds are obtained by a method similar to ReferenceExample 1.

4-[(4-Tolyl)acetyl]cinnamic acid (Reference compound No. 1-2)

4-[(4-Fluorophenyl)acetyl]cinnamic acid (Reference compound No.1-3)

4-[(4-Chlorophenyl)acetyl]cinnamic acid (Reference compound No. 1-4)

REFERENCE EXAMPLE 2

3-[4-(Phenylacetyl)phenyl]propionic Acid (Reference compound No. 2-1)

1) Phenylacetyl chloride (3.4 ml) is added to a solution of anhydrousaluminum chloride (4.27 g) in 1,2-dichloroethane (35 ml) under icecooling, and then a solution of ethyl 3-phenylpropionate (5.1 g) inanhydrous 1,2-dichloroethane (5 ml) is added dropwise thereto. Themixture is stirred under ice cooling for 20 minutes and at roomtemperature overnight. The reaction mixture is added little by little toa saturated aqueous sodium hydrogencarbonate solution (150 ml)containing ice (100 g). The resulting precipitates are filtered out.Ether is added to the filtrate. The organic layer is washed with asaturated aqueous sodium hydrogencarbonate solution and saturated brinesuccessively, dried over anhydrous magnesium sulfate and concentratedunder reduced pressure. The resulting residue is purified by silica gelcolumn chromatography to give ethyl 3-[4-(phenylacetyl)phenyl]propionateas crystals.

mp 50.5˜52.5° C.; IR (KBr, cm⁻¹) 3059, 2977, 2921, 1735, 1682, 1605,1479, 1455, 1437, 1357, 1316, 1181, 822.

2) A 1 N aqueous sodium hydroxide solution (3.1 ml) is added to asolution of ethyl 3-[4-(phenylacetyl)phenyl]propionate (700 mg) inethanol (6 ml)-tetrahydrofuran (3 ml), and the mixture is stirred atroom temperature for two hours. A 10% aqueous citric acid solution isadded to the reaction mixture to acidify it, and the whole is extractedwith ethyl acetate. The organic layer is washed with water and saturatedbrine successively, dried over anhydrous sodium sulfate and concentratedunder reduced pressure. The resulting precipitates are filtered off togive the titled compound (Reference compound No. 2-1) as crystals.

(Reference compound No. 2-1)

mp 132˜137° C. IR (KBr, cm⁻¹) 3497, 3028, 1680, 1607, 1498, 1455, 1348,1221, 1182, 992, 826.

REFERENCE EXAMPLE 3

N,N-Dimethyl-4-(phenylacetyl)cinnamamide (Reference compound No. 3-1)

To a solution of 4-(phenylacetyl)cinnamic acid (Reference compound No.1-1, 3.23 g) in anhydrous tetrahydrofuran (120 ml) chloroform (20 ml)are added 1-hydroxybenzotriazole (1.64 g), dimethylamine hydrochloride(1.19 g), N-methylmorpholine (3.1 ml) and1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (2.56 g),and the mixture is stirred at room temperature for five hours. Thereaction mixture is concentrated under reduced pressure, a 10% aqueouscitric acid solution is added to the concentrate, and the whole isextracted with ethyl acetate. The organic layer is washed with water, asaturated aqueous sodium hydrogencarbonate solution, water and saturatedbrine successively, dried over anhydrous magnesium sulfonate andconcentrated under reduced pressure. The resulting precipitates arefiltered off to give the titled compound (Reference compound No. 3-1,3.00 g) as crystals.

(Reference compound No. 3-1)

mp 138.5˜141.5 ° C.; IR (KBr, cm⁻¹) 3030, 1684, 1653, 1604, 1498,1413,1328, 1205, 992, 967.

The following compounds are obtained by a method similar to ReferenceExample 3.

N,N-Dimethyl-3-[4-(phenylacetyl)phenyl]propionamide (Reference compoundNo. 3-2)

mp 125˜131 ° C.; IR (KBr, cm⁻¹) 3028, 2908, 1684, 1640, 1604, 1495,1452, 1407, 1141.

N,N-Dimethyl-4-[(4-tolyl)acetyl]cinnamamide (Reference compound No. 3-3)

N,N-Dimethyl-4-[(4-fluorophenyl)acetyl]cinnamamide (Reference compoundNo. 3-4)

4-[(4-Chlorophenyl)acetyl]-N,N-dimethylcinnamamide (Reference compoundNo. 3-5)

4-(Phenylacetyl)cinnamamide (Reference compound No. 3-6)

EXAMPLE 1

1-[4-[(E)-3 -(Dimethylamino)-1-propenyl]phenyl]-2-phenyl-1-ethanolHydrochloride (Compound No. 1-1)

A solution of N,N-dimethyl-4-(phenylacetyl)cinnamamide (Referencecompound No. 3-1, 3.00 g) in anhydrous tetrahydrofuran (72 ml) is addeddropwise to a suspension of lithium aluminum hydride (0.58 g) inanhydrous tetrahydrofuran (30 ml) under ice cooling and a nitrogenatmosphere. After completing the addition, the mixture is stirred atroom temperature for 20 minutes.

Anhydrous sodium sulfate is added to the reaction mixture, and water isadded dropwise thereto with stirring. The resulting insoluble matter isfiltered out, and the filtrate is concentrated under reduced pressure.The resulting residue is purified by silica gel column chromatographyand dissolved in a 4.0 N solution of hydrogen chloride in ethyl acetate.After vacuum concentration, the resulting precipitates are filtered offto give the titled compound (Compound No. 1-1, 0.80 g) as crystals.

(Compound No. 1-1)

mp 152˜164° C.; IR (KBr, cm⁻¹⁾ 3334, 2954, 2664, 1650, 1418, 1161, 1034,984, 752, 708.

The following compounds are obtained by a method similar to Example 1.

1-[4-[3-(Dimethylamino)propyl]phenyl]-2-phenyl-1-ethanol (Compound No.1-2)

IR (Film, cm⁻¹) 3026, 2941, 2860, 2778, 1495, 1454, 1042.

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-(4-tolyl)-1-ethanol(Compound No. 1-3)

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-(4-fluorophenyl)-1-ethanol(Compound No. 1-4)

2-(4-Chlorophenyl)-1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl]-1-ethanol(Compound No. 1-5)

1-[4-[(E)-3-Amino-1-propenyl]phenyl]-2-phenyl-1-ethanol (Compound No.1-6).

EXAMPLE 2

1-[4-[(E)-3-(Acetylamino)-1-propenyl]phenyl]-2-phenyl-1-ethanol(Compound No. 2 -1)

1-[4-[(E)-3-Amino-1-propenyl]phenyl]-2-phenyl-1-ethanol (Compound No.1-6) is treated with acetic anhydride in pyridine to give the titledcompound (Compound No. 2-1).

EXAMPLE 3

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-phenyl-1-ethanone(Compound No. 3-1)

Triethylamine (2.1 ml) is added to a solution of1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl]-2-phenyl-1-ethanolhydrochloride (Compound No. 1-1, 800 mg) in dimethyl sulfoxide (15 ml)at room temperature with stirring, and further a solution of a sulfurtrioxide-pyridine complex (1.6 g) in dimethyl sulfoxide (10 ml) is addeddropwise thereto. The mixture is stirred at room temperature for threehours, a 0.1 N aqueous sodium hydroxide solution is added to thereaction mixture, and the whole is extracted with ether. The organiclayer is washed with saturated brine, dried over anhydrous magnesiumsulfate and concentrated under reduced pressure. The resulting residueis purified by silica gel column chromatography to give the titledcompound (Compound No. 3-1, 270 mg) as crystals.

(Compound No. 3-1)

IR (KBr, cm¹) 2767, 1682, 1599, 1452, 1408, 1332, 1219, 1175, 975, 726,697.

The following compounds are obtained by a method similar to Example 3.

1-[4-[3-(Dimethylamino)propyl]phenyl]-2-phenyl-1-ethanone (Compound No.3-2)

mp 37.8˜40.0 ° C.; IR (KBr, cm⁻¹⁾ 2809, 2758, 1682, 1601, 1565, 1493,1453, 1409.

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-(4-tolyl)-1-ethanone(Compound No. 3-3)

1-(4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-(4-fluorophenyl)-1-ethanone(Compound No. 3-4)

2-(4-Chlorophenyl)-1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl]-1-ethanone(Compound No. 3-5)

1-[4-[(E)-3-(Acetylamino)-1-propenyl]phenyl]-2-phenyl-1-ethanone(Compound No. 3-6).

EXAMPLE 4

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-phenyl-2-propen-1-one(Compound No. 4-1)

A solution of1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl]-2-phenyl-1-ethanone(Compound No. 3-1, 200 mg) in dioxane (10 ml) is introduced into apressure tube. To the solution are added paraformaldehyde (86 mg),dimethylamine hydrochloride (233 mg), acetic acid (one drop) andanhydrous magnesium sulfate (1 g), and the whole is stirred overnightwhile heating it at 120° C. A saturated aqueous sodium hydrogencarbonatesolution is added to the reaction mixture under ice cooling to basifyit, and the whole is extracted with ethyl acetate. The organic layer iswashed with saturated brine, dried over anhydrous magnesium sulfate andconcentrated under reduced pressure. The resulting residue is purifiedby silica gel column chromatography to give the titled compound(Compound No. 4-1, 145 mg).

(Compound No. 4-1)

IR (Film, cm⁻¹) 2941, 2771, 1664, 1601, 1412, 1217, 1175, 980, 700.

The following compounds are obtained by a method similar to

EXAMPLE 4

1-[4-[3-(Dimethylamino)propyl]phenyl]-2-phenyl-2-propen-1-one (CompoundNo. 4-2)

IR (KBr, cm⁻¹) 3416, 3027, 2942, 2814, 2765, 1665, 1604, 1465, 1415,981, 915.

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-(4-tolyl)-2-propen-1-one(Compound No. 4-3)

1-[4-[(E)-3-(Dimethylamino)-1-propenyl]phenyl]-2-(4-fluorophenyl)-2-propen-1-one(Compound No. 4-4)

2-(4-Chlorophenyl)-1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl]-2-propen-1-one(Compound No. 4-5)

1-[4-[(E)-3-(Acetylamino)-1-propenyl]phenyl]-2-phenyl-2-propen-1-one(Compound No. 4-6).

Formulation

Formulation examples of eyedrops and oral preparation using the presentcompound are shown below.

1) Eyedrops In 10 ml Present compound 1 mg Concentrated glycerin 250 mg Polysorbate 80 200 mg  Sodium dihydrogenphosphate dihydrate 20 mg  1NSodium hydroxide q.s. 1N Hydrochloric acid q.s. Sterile purified waterq.s. 2) Tablet In 100 mg Present compound 1 mg Lactose 66.4 mg  Cornstarch 20 mg  Calcium carboxymethylcellulose 6 mgHydroxypropylcellulose 6 mg Magnesium stearate 0.6 mg  

Pharmacological Test

In order to study utility of the present compounds in glaucoma, effectsof the present compounds on morphology of trabecular meshwork cells wereinvestigated.

1) Effects on Morphology of Trabecular Meshwork Cells

The possibility has been reported that drugs having effects ofincreasing aqueous humor outflow can be found by evaluating effects ofdrugs on morphology of cultured trabecular meshwork cells (Invest.Ophthalmol. Vis. Sci., 33, 2631-2640 (1992)). Accordingly, effects ofthe present compounds on morphology of bovine cultured trabecularmeshwork cells were studied in the similar manner to the methoddescribed in the above-mentioned literature.

Experimental Method

Morphological changes in bovine cultured trabecular meshwork cells byadding the present compounds were quantitatively evaluated by imageanalysis.

Preparation of Cells

Bovine trabecular meshwork cells (passage number 2 to 5) cultured in abasal medium for mammalian cell culture D-MEM (Dulbecco's Modified EagleMedium, manufactured by Gibco Co., Ltd.) containing fetal bovine serum(10%), amphotericin B (2.5 μg/ml) and gentamicin (50 μg/ml) were treatedwith a trypsin-EDTA solution (0.05% trypsin, 0.53 mM EDTA·4Na) 24 hoursbefore the later drug treatment and seeded in a 24-well plate (10⁴cells/well). Twelve hours before the later drug treatment, the cellswere washed with phosphate-buffered physiological saline, and then themedium was replaced by D-MEM containing amphotericin B (2.5 μg/ml) andgentamicin (50 μg/ml) (hereinafter referred to as “medium A”). One hourbefore the later drug treatment, cells which did not contact each otherwere selected from the cells prepared as mentioned above and used forexperiment.

Preparation of Test Compound Solution

A test compound was dissolved in dimethyl sulfoxide (DMSO), and themedium A was added to the solution, followed by sterilizing the solutionby filtration. The medium A was further added to the solution to diluteit at a prescribed concentration. This diluted solution was maintainedisothermally under a 5% carbon dioxide gas atmosphere at 37° C. for onehour, from one hour before the later drug treatment to prepare a testcompound solution.

Method of Measurement

First, cells were photographed using a well-scanner one hour before thedrug treatment. Next, the medium of the cells was replaced by the testcompound solution, and the cells were treated with the drug andincubated under a 5% carbon dioxide gas atmosphere at 37° C. for threehours. Then, the same cells as those photographed one hour before thedrug treatment were photographed using the well-scanner.

Image Analysis

Photographed cell images were incorporated from the photographs into animage analysis system with a CCD camera (manufactured by HAMAMATU Co.,Ltd.). Outlines of the incorporated cell images were traced, and areaswere measured. Degrees of the morphological changes made by the testcompounds on the trabecular meshwork cells are expressed by thefollowing rates of changes in areas (%).

Rate of change in area (%)=[(A-B)/A]×100

A: Cell area before drug treatment

B: Cell area after drug treatment

Results

Table 1 shows concentrations required to reduce the cell area of thetrabecular meshwork cells by 50%, i.e., EC₅₀, as examples of testresults. Table 1 shows also a result using ethacrynic acid as a controldrug.

TABLE 1 Test compound EC₅₀ (M) Compound No. 4-1 5.8 × 10⁻⁷ Compound No.4-2 8.4 × 10⁻⁷ Ethacrynic acid 6.2 × 10⁻⁵

Table 1 shows that the present compounds have excellent cellmorphological change effects on the trabecular meshwork cells. Theseeffects were much higher than that of ethacrynic acid, which was a knowncomparative control drug.

The above-mentioned results show that the present compounds. have theexcellent cell morphological change effects and are useful asintraocular pressure-lowering agents, namely therapeutic agents forglaucoma.

Industrial Applicability

The present invention provides compounds which lower intraocularpressure by causing morphological change in trabecular meshwork cells.These compounds are useful as therapeutic agents for glaucoma.

What is claimed is:
 1. A compound represented by the following formulaor a salt thereof,

wherein R¹ is hydrogen, lower alkyl, hydroxy, lower alkoxy or halogen,R², R³ and R⁴ are the same or different and are hydrogen or lower alkyl,and . . . is a single bond or a double bond.
 2. The compound or a saltthereof as claimed in claim 1, wherein R³ and/or R⁴ is hydrogen, and theamino group is protected by a protecting group.
 3. The compound or asalt thereof as claimed in claim 1, wherein R¹ is a group selected fromhydrogen, lower alkyl and halogen.
 4. A compound or a salt thereof asclaimed in claim 1, wherein the compound is1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl-2-phenyl-2-propen-1-one.5. A pharmaceutical composition comprising a pharmaceutically effectiveamount of the compound or a salt thereof as claimed in claim 1 as anactive ingredient in combination with a pharmacologically acceptablecarrier.
 6. A method for improving aqueous humor outflow in a patientcomprising administering to a patient a pharmaceutically effectiveamount of the compound or a salt thereof as claimed in claim 1 as anactive ingredient.
 7. A method for lowering intraocular pressure in apatient comprising administering to a patient a pharmaceuticallyeffective amount of the compound or a salt thereof as claimed in claim 1as an active ingredient.
 8. A compound represented by the followingformula or a salt thereof,

wherein R¹ is hydrogen, lower alkyl, hydroxy, lower alkoxy or halogen,R², R³ and R⁴ are the same or different and are hydrogen or lower alkyl,. . . is a single bond or a double bond, >X is >CHOH or >C═O, and whenR³ and/or R⁴ is hydrogen, the amino group is unprotected or protected bya protecting group.
 9. The compound or a salt thereof as claimed inclaim 1, wherein R² is hydrogen.
 10. The compound or a salt thereof asclaimed in claim 3, wherein R² is hydrogen.
 11. The compound or a saltthereof as claimed in claim 1, wherein both R³ and R⁴ are lower alkyl.12. The compound or a salt thereof as claimed in claim 3, wherein bothR³ and R⁴ are lower alkyl.
 13. The compound or a salt thereof as claimedin claim 10, wherein both R³ and R⁴ are lower alkyl.
 14. The compound ora salt thereof as claimed in claim 1, wherein the compound is1-[4-[3-(dimethylamino)propyl]phenyl-2-phenyl-2-propen-1-one.
 15. Themethod as claimed in claim 6, wherein the compound is selected from thegroup consisting of1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl-2-phenyl-2-propen-1-oneand 1-[4-[3-(dimethylamino)propyl]phenyl-2-phenyl-2-propen-1-one. 16.The method as claimed in claim 7, wherein the compound is selected fromthe group consisting of1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl-2-phenyl-2-propen-1-oneand-1-4-[13-(dimethylamino)propyl]phenyl-2-phenyl-2-propen-1-one. 17.The composition as claimed in claim 5, wherein the compound is selectedfrom the group consisting of1-[4-[(E)-3-(dimethylamino)-1-propenyl]phenyl-2-phenyl-2-propen-1-oneand 1-[4-[3-(dimethylamino)propyl]phenyl-2-phenyl-2-propen-1-one.